By Lilian Anekwe
A new diagnostic test for Barrett's oesophagus could be the foundation of a screening programme in primary care, according to UK-led research.
The researchers, from the University of Cambridge, said the promising performance of the Cytosponge test means a screening programme for the condition – the main risk factor for oesophageal cancer - had been brought ‘into the realm of possibility'.
The ideal method for diagnosing Barrett's oesophagus is gastroscopy and biopsy, which has held back a screening programme because of its invasiveness, high cost and the subjective nature of the diagnosis.
The Cytosponge is a gelatine capsule attached to a string which is swallowed and then dissolves in the proximal stomach, releasing a 3cm spherical mesh.
The mesh is then withdrawn and immunostained for trefoil factor 3, a biomarker for Barrett's oesophagus.
In the evaluation 500 patients in 12 UK general practices were tested using the Cytosponge. They then had an endoscopy to explore the sensitivity and specificity of the biomarker. All were aged between 50 and 70 and had taken acid suppression for more than three months in the past five years.
Gastroscopy revealed 3% of patients had Barrett's oesophagus with intestinal metaplasia – a marker for oesophageal cancer.
Compared with gastroscopy the sensitivity and specificity of the test was 73.3% and 93.8% and well tolerated, as 82% of patients reported low levels of anxiety about the test.
Writing in the BMJ, the researchers said they hoped their evaluation would turn the tide of evidence, which currently suggests that primary care screening of patients with Barrett's oesophagus is not cost-effective.
Lead researcher Dr Rebecca Fitzgerald, consultant gastroenterologist at Addenbrooke's hospital in Cambridge concluded: ‘We've shown that the Cytosponge is a promising tool to screen for Barrett's oesophagus in primary care and that further evaluation is warranted. These results bring screening for Barrett's oesophagus into the realm of possibility.'
In an accompanying editorial Dr Peter Bampton, a gastroenterologist at Flinders University in Adelaide called the results exciting and added: ‘Future screening and surveillance for Barrett's oesophagus might use a two step approach, with endoscopy being reserved to confirm the diagnosis in the screened.'
BMJ, published online 10 September 2010.Barrett's oesophagus is the main risk factor for oesophageal cancer Barrett's oesophagus is the main risk factor for oesophageal cancer